Most outbreaks of foodborne illness in the United States occur as a result of improper food-handling and preparation practices in homes or food establishments. Some food-safety recommendations that are difficult to incorporate into handling and cooking procedures have contributed to a gap between food-safety knowledge and the actual behavior. The first part (Chapter 3, 4) of this study sought to ensure microbial safety by establishing alternative processing of meat products that can be easily practiced by food-operators and consumers. In Chapter 3, a novel method was developed to thaw frozen chicken-breast by submersion in hot water at 60 °C, an appropriate temperature setting for foodservice hot-holding equipment. This method is rapid (compared to either refrigerator or cold-water thawing that also uses a significant amount of water), safe, and the final cooked-product sensory-quality was not different from refrigerator-thawed and cooked product (microwave thawing results in localized overheating). Chapter 4 developed marinade-cooking (91 °C) and holding (60 °C) procedures for hamburger-patties. Frozen patties were partially grilled and finished cooking in marinade. The moderate temperature of marinade cooking overcomes the chances of thick-patties being surface-overcooked while innermost portions remain undercooked as seen in high-temperature cooking methods (grilling and pan-frying). Consumers liked the marinade-finished cooked and held patties (up to 4 h) equally or more (holding-time dependent) compared to patties grilled and held in a hot-steam cabinet. Reducing salt in perishable foods including cheese is microbial-safety concern especially in their distribution and storage. The second part (Chapter 5, 6) of this study sought to evaluate microbial safety of low-salt hard-type cheese. Aged Cheddar cheeses were inoculated with either Listeria monocytogenes (3.5 log CFU/g) or Salmonella spp. (4.0 log CFU/g) and their survival or growth was monitored at 4, 10, and 21°C for up to 90, 90, and 30 d, respectively. Low-salt (0.7% NaCl) Cheddar formulated at pH 5.1 or 5.7 exhibited no-growth or gradual reduction in L. monocytogenes and Salmonella counts. The results suggest that low-salt Cheddar is as safe as its full-salt counterparts (1.8% NaCl) and that salt may only be a minor food-safety hurdle regarding the post-aging contamination and growth of L. monocytogenes and Salmonella.

The plant hormone, abscisic acid (ABA), has previously been shown to have an impact on the resistance or susceptibility of plants to pathogens. In this thesis, it was shown that ABA had a regulatory effect on an extensive array of plant defence responses in three different plant and pathogen interaction combinations as well as following the application of an abiotic elicitor. In unique studies using ABA deficient mutants of Arabidopsis, exogenous ABA addition or ABA biosynthesis inhibitor application and simulated drought stress, ABA was shown to have a profound effect on the outcome of interactions between plants and pathogens of differing lifestyles and from different kingdoms. The systems used included a model plant and an important agricultural species: Arabidopsis thaliana (Arabidopsis) and Peronospora parasitica (a biotrophic Oomycete pathogen), Arabidopsis and Pseudomonas syringae pathovar tomato (a biotrophic bacterial pathogen) and an unrelated plant species, soybean (Glycine max) and Phytophthora sojae (a hemibiotrophic Oomycete pathogen), Generally, a higher than basal endogenous ABA concentration within plant tissues at the time of avirulent pathogen inoculation, caused an interaction shift towards what phenotypically resembled susceptibility. Conversely, a lower than basal endogenous ABA concentration in plants inoculated with a virulent pathogen caused a shift towards resistance. An extensive suppressive effect of ABA on defence responses was revealed by a range of techniques that included histochemical, biochemical and molecular approaches. A universal effect of ABA on suppression or induction of the phenylpropanoid pathway via regulation of the key entry point gene, phenylalanine ammonia-lyase (PAL), when stimulated by biotic or abiotic elicitors was shown. ABA also influenced a wide variety of other defence-related components such as: the development of a hypersensitive response (HR), the accumulation of the reactive oxyden species, hydrogen peroxide and the cell wall strengthening compounds lignin and callose, accumulation of SA and the phytoalexin, glyceollin and the transcription of the SA-dependent pathogenesis- related gene (PR-1). The near genome-wide microarray gene expression analysis of an ABA induced susceptible interaction also revealed an yet unprecedented insight into the great diversity of defence responses that were influenced by ABA that included: disease resistance like proteins, antimicrobial proteins as well as phenylpropanoid and tryptophan pathway enzymes. Subtle differences were found in the number and type of defence responses that were regulated by ABA in each type of plant and pathogen interaction that was studied. This thesis has clearly identified in plant/pathogen interactions previously unknown and important roles for ABA in the regulation of many defence responses.

<p> </p><p><strong>Conclusion:</strong>Medical treatment may have a role in platelet count after transfusion. Since the TACSI platelets passed the quality requirements, and the vast majority of patients platelet count increased after TACSI platelet transfusion, the TACSI platelets will replace the old method to produce platelets at the Uppsala University hospital.</p><p> </p><p> </p><p><strong>Methods:</strong> A new approach that pools 8 buffy coats (TACSI platelets) that were separated into 2 units instead of 4-6 buffy coats pooled to 1 unit was investigated in this study. After the platelets were extracted from the buffy coats their quality was controlled and subsequently the platelet product was evaluated in 96 patients.</p><p> </p><p><strong>Results:</strong> The results showed that 80 % of the platelet units passed the European quality requirements. Further, the platelet count was increased in most patients that received TACSI platelets.</p><p><strong> Conclusion:</strong> Medical treatment may have a role in platelet count after transfusion. Since the TACSI platelets passed the quality requirements, and the vast majority of patients platelet count increased after TACSI platelet transfusion, the TACSI platelets will replace the old method to produce platelets at the Uppsala University hospital.</p><p> </p><p> </p><p> </p>

<p>Recent research in microbial ecology has focused on how aquatic bacterial communities are assembled. Only a few of these studies follow a “Gleasonian” approach where the roles of single bacterial populations are in focus. In this thesis, novel molecular tools were used to describe the distribution and evolutionary relationships of microbes in productive aquatic environments. Many new phylogenetic groups of bacteria were identified, likely representing bacterial populations restricted to productive freshwaters. I also addressed the dynamics and functional role of individual bacterial populations in eutrophic lakes and brackish environments with a focus on either biogeochemically significant or potentially pathogenic representatives. <i>Flavobacteria</i> blooms were observed, on occasions characterized by high heterotrophic production. In addition to high temporal dynamics microbial community composition and function differed on the spatial scale, as exemplified by free-living and <i>Cyanobacteria</i>-associated habitats. At the community scale, microbial processes, such as biomass production and substrate uptake could be predicted from the presence and absence of individual bacterial populations. I also studied the niches of potentially pathogenic <i>Vibrio </i>populations in various coastal waters. Using a novel culture-independent method, a <i>V. cholerae</i> population was detected along the entire Swedish coastline. Results from an environmental survey and a laboratory mesocosm experiment reveal that phytoplankton-derived dissolved organic matter enhance the growth of <i>V. cholerae</i> and other <i>Vibrio</i> spp. and hence create a largely overlooked niche for these heterotrophic bacteria. This thesis and future work on the role of individual bacterial populations will facilitate predictions of biogeochemical cycles and the distribution of bacteria in the context of global climate change and local eutrophication.</p>

Thesis (M.S.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 41-47). Also available on the World Wide Web.

Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 103-124).

Detection of cellular messenger RNA is a useful diagnostic strategy for the detection of patho-gens. A rapid and sensitive method for on-site detection of specific pathogens would be of great use in a number of fields. For example, a simple and inexpensive method for the detection of harmful biological agents in train stations and airports is useful for national security. Rapid detection of pathogenic E. coli strains in food production would also be of great benefit in ensuring the safety and quality of our food supply. Here we present a method for the rapid de-tection of cellular mRNA. This system is based on the 3’-labeling approach in which targeted RNA is simultaneously extended and labeled with the use of biotin labeled-dNTPs and DNA po-lymerase on an immobilized nucleic acid probe. The biotin is subsequently converted to an enzymatic label, which produces a detectable chemiluminescent reaction in the presence of substrate. Detection time of this system is short (approximately 20 minutes) because there is no need for amplification by PCR, transcription, or fluorophore labeling. This novel methodology has been successfully demonstrated by selective detection of lac Z mRNA in a total RNA sample from E. coli.

Pseudomonas syringae pv. syringae strain B728a (P.s.s. B728a) is an economically significant plant pathogen that is capable of successful epiphytic colonization of leaf surfaces. Although the virulence factors associated with this pathogen’s ability to cause disease have been well studied, the transition from epiphyte to pathogen is not well understood. The research described in this dissertation utilizes high throughput sequencing transcriptome analyses to define an iron regulatory network that is predicted to be utilized during the epiphytic portion of the P.s.s. B728a lifecycle. This dissertation also describes a collaborative microarray analysis that analyzes the P.s.s. B728a transcriptome at a global level. An iron associated sigma factor, AcsS, encoded within a peptide synthesis rich region of the P.s.s. B728a genome is shown to regulate the citrate siderophore achromobactin. RNA-seq transcriptome analysis reveals that this sigma factor regulates expression of genes predicted to be involved in functions that are important during the epiphytic stage of P.s.s. B728a, including genes involved in iron response, secretion, extracellular polysaccharide production, and cell motility. As part of a collaboration, the transcriptomes of the P.s.s. B728a genome and nine deletion mutants in regulatory genes were analyzed by microarray analayses using seven treatment conditions, including epiphytic and in planta conditions. As part of these microarray analyses, results are described for the global regulator, GacS, and a downstream transcription factor, SalA. This study confirms the role of GacS and SalA in the regulation of major virulence components of P.s.s. B728a such as phytotoxin production and Type III secretion. This study also elucidates a role for GacS and SalA regulation of genes important for epiphytic survival and function, including the Type VI secretion system, iron acquisition, and EPS production.

The beef industry has made tremendous strides in reducing pathogen contamination on carcasses. Multiple antimicrobial interventions have been validated for their use during harvesting. Information in regards to cross-contamination with pathogens in the post-harvest environment is limited. Surrogate microorganisms for enteric pathogens are commonly used to validate antimicrobial interventions and might allow for the simulation of cross-contamination through the post-harvest environment. The purpose of this study was to determine how the post-harvest environment impacts the direct and indirect transmission of pathogens. This was achieved by using fluorescent protein-marked surrogate strains of Escherichia coli O157:H7 and Salmonella spp. from inoculated carcasses to the adjacent ones and to the equipment and facility in three different abattoirs. Thirteen hide-on carcasses were inoculated using a gelatin-based slurry containing three nonpathogenic fluorescent protein-marked strains of E. coli biotype I. In order to determine direct and indirect cross-contamination, inoculated and adjacent carcasses were sampled (300 cm2) during the harvesting process at different stages: after hide opening (AHO), prior to evisceration (PE), after evisceration (AE), after splitting (AS), and after final intervention (AFI). Environmental samples consisting of the floor, walls, and air were tested as well as personal equipment including gloves, boots, and aprons. Equipment including hand knives, air knives, meat hooks, hide puller and split saw were also sampled. Results showed evidence of cross-contamination between inoculated carcasses and the adjacent non-inoculated ones for all abattoirs. Although this occurred in all abattoirs, surrogate counts on carcasses were below detectable levels (<1.4 log CFU/cm2) after antimicrobial interventions. Surrogates were found in low levels for all environmental samples. However surrogate counts from equipment such as knives, split saws, meat hooks, and hide puller were more frequently detected (15 percent) than those found on the floor, air and walls samples (10 percent). In the case of aprons, boots, and gloves, the prevalence of countable surrogate samples was 7 percent.

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: protein interaction; coat protein; resistance; arabidopsis; turnip crinkle virus. Includes bibliographical references (p. 58-62).